Total replacement of the anatomical knee joint with a prosthetic joint has become an accepted, increasingly commonplace, surgical procedure. At the present time the femoral prosthesis is provided with symmetrical medial and lateral condyles. The disadvantage of the use of this type of prosthesis in total knee arthroplasty surgery results in excessive compression force on the patellar component at the patella lateral femoral condyle articulation producing patellar component failure with unacceptable frequency and decreased range of motion due to the tightness of the patella as it moves over the condyle during flexion and extension of the knee.
The shape of the prosthesis is one of the most important factors influencing post-operative knee function and the duration of prosthesis survival.